I was asked by a customers mother to clean their con roof and fascias. Whilst i was pricing it up, asked her if wanted a quote for windows on a regular basis. She told me she had a regular window cleaner and so in a nice way asked why she got me as ive come out my way for this (only because ive done daughters for last 14 yrs n a good customer). The answer was simple, she knew ive done daughters several times and she was satisfied (no jokes lads) but also i had profesional equipment, in her words to do it and trusted me to do so. So guessing has cowboys or chaffs cleaning windows
But another option, most likely option sometimes as this has also happened to me. A customer got someone else to do gutters/fascia because they charged a silly low price for doing so, compared to my quote. The house was small n at the time my price plan for my area, was £25 per side. This house had 3 sides, so 75. They charged 25 for job lot...